The National Trust has just made it easier to visit their many properties with the launch of a new app for the iPhone and has announced it will be free entry during their ‘Bonus Time Weekend‘ on 20/21 March 2010.

The free application not only gives information about all the National Trust’s 350-plus properties and 600,000 acres of countryside but also other local attractions, routes and stop-offs. Using location awareness, the app will let you know what properties are within 20-, 30-, and 40-miles of your current position but you can also just browse a complete list of all properties.

So how best to use their app? Well, if you’re not one of their 3.8m members already, this coming weekend – 20/21 March – you can use this voucher to gain free entry to any of their properties which you would normally have to pay for. See the full list of participating venues to see what’s close to you.